Closed circuit television (CCTV) systems are commonly used for video surveillance operations, such as for security applications and night vision. Traditional CCTV cameras operate mainly with the visible light spectrum and are blind in conditions of darkness, such as during the night or in enclosed spaces within buildings. CCTV cameras are available that can operate with either the visible light spectrum or infrared spectrum. It is often desirable to be able to zoom in on areas with suspicious or interesting activity, and CCTV cameras may include pan-tilt-zoom (PTZ) features to allow viewing of particular areas of interest. Illuminators are frequently used to provide visible and/or infrared light that is sufficient for wide-angle views, typically with a viewing angle of 120-140 degrees. However, these illuminators generally do not provide sufficient light for narrow angle long-range viewing.
Traditional zoom lenses for CCTV cameras are relatively large and motorized. Thus, they are bulky as well as mechanically and electronically complex. Particularly for applications where the camera is located outdoors, maintaining proper mechanical operation under severe weather conditions can be difficult. In recent years, digital zoom technology has been developed, allowing selection of portions of a wide-angle image for more detailed viewing. Digital zoom technology is accomplished via processing of the image received from a camera, requiring neither complex electronics nor complex mechanical systems within the camera. The images can be processed at a remote location.
Thus, there is a need for an illumination system that provides sufficient illumination for use with zoom features in CCTV cameras, particularly for digital zoom features.
There is also a need for a zoom illumination system that operates without moving parts.
There is a further need for a zoom illumination system that is energy-efficient.